1. Technical Field
A micro-resonator structure depends upon cavitation of whispering mode energy regardable as defining cavitation about the perimeter of a sub-wavelength thick active region of various configurations. Operating in the lasing mode, it offers an alternative to the Surface Emitting Laser for incorporation in integrated circuitry--either all-optic or electro-optic.
2. Description of the Prior Art
A general category of structures includes optical detectors as well as a variety of two port and three port devices providing for modification either of output or input. Worldwide activity is consistent with the consensus that the SEL offers promise of satisfaction of the longstanding desire for large-scale incorporation of active photonic devices in integrated circuits. Hope is based on the very low lasing threshold values which intrinsically reduce heating, usually I.sup.2 R heating losses attendant on pumping considered central to frustration of this desire.
Development of the SEL has entailed a number of design advances. Use of bulk active material has, to significant extent, yielded to quantum well structures--including the ultimate single quantum well structure. Process variations have involved deposition techniques with a view both to compositional uniformity and dimensional regularity. An area of considerable consequence has involved the sandwiching Distributed Bragg Reflector mirrors. Reported operating devices dependably achieve reflectivities of 99+% as yielded by .apprxeq.20-40 pair DBRs for 0.8-1.1 .mu.m wavelength emission. This latter consideration--definition of the laser cavity in terms of DBRs--has been of primary consequence in evolution of the SEL. Achievement of excellent reported reflectivities is ascribed to satisfaction of very tight fabrication tolerances.
On the other side of the ledger, achievement of each new SEL design has depended critically on the DBR to, in turn, result in considerable expense as well as some undesirable operational consequence. DBRs, as the name connotes, is distributed-significantly increases modal volume beyond that of the responsible active region. In the instance of a Single Quantum Well structure designed for operation at 1.3 .mu.m, this consideration results in an increase of 20.times..